Starters Kenny Stills and DeVante Parker are nursing injuries but might have sat out anyway, because coaches use the last preseason game mostly to evaluate the back end of the roster.

That includes such youngsters as Carroo and Grant, who bunked together during training camp while competing for playing time. Both are sure to make the team, but eager to climb higher on the depth chart.

Carroo, a third-round draft pick from Rutgers, has yet to make much of a splash during the preseason. Grant, a sixth-round choice from Texas Tech, has been more eye-catching, in part because he's just 5-foot-6 - apparently even shorter than he looks on TV.

''On the field a lot of people tell me, `I didn't know you were that small,''' Grant said. ''In my heart, I'm just as big as anybody else, and I don't think it's a disadvantage at all. I think it's more of an advantage to me. They're not used to tackling smaller guys like me.''

Carroo, by contrast, is 6-1 and 217 pounds.

''I'm a physical receiver who is going to make the tough catches,'' Carroo said, ''a guy who likes to catch a lot of passes and score a lot of touchdowns.''

The two rookies will likely play most of the game while paired with reserve quarterbacks Zac Dysert and Brandon Doughty, both battling to make the roster as a third-stringer. Rookie running back Kenyan Drake is also slated for significant action after missing the first three exhibition games because of a hamstring injury.

Coach Adam Gase said he wants to see Carroo and Grant in the right spot at the right time.

''Both of those guys have had mistakes where the quarterback thinks they're going to do one thing, and they do something different,'' Gase said. ''We'd like for them to be as sound as possible.''

With limited action in the first three exhibition games, Grant had five receptions for 73 yards, and Carroo had four for 23.

''This is something I've been looking forward to in training camp - to play a whole game and showcase what I can bring to this offense,'' Carroo said.

The receiving group took a double whammy Monday when Stills and Parker left practice with injuries. Stills' back locked up, and Parker has been slowed by a sore hamstring, but both took part in Tuesday's walkthrough. Guard Laremy Tunsil also was back after leaving Monday's practice with a foot injury.

For the rookies, the injuries were a reminder second-stringers are always on standby.

''I'm sorry my teammates went down,'' Grant said, ''but we shouldn't have a drop-off just because they're out.''

Grant's always trying to win a job returning punts and kickoffs. He ran back kickoffs in college, but never fielded punts until he joined the Dolphins and admitted to jitters in the first preseason game.

''I think all the jitters are out,'' he said. ''No bad moments go through my head. Kickoff returns, I feel great. It's kind of the same as college - you don't want to spend too much time dancing. Go north and take it to the house.''